Deploying to Kubernetes
On a dev cluster, deploying a flow is one command:
videoflow deploy my_flow.py
A graph with no Dockerfile next to it — the Quickstart’s my_flow.py — runs
its built-in nodes in the videoflow base image for your version (deploy says
so); a Dockerfile next to the graph, your nodes and their dependencies on
top of that base, is built and used instead, and --image overrides either.
The argument names a solution directory in one of three ways; see
Prerequisites below.
deploy is a one-stop pipeline: every step below runs automatically by
default, and every step has an explicit flag to do it manually instead. The
same graph you run locally deploys unchanged.
What videoflow deploy does, step by step
Config — if the solution ships a
config.template.yamland there is noconfig.yamlnext to the graph, deploy asks the template’sx-questionsinteractively on the terminal and writesconfig.yaml. An existingconfig.yaml(or--config PATH) is used as-is. In a non-interactive session (--non-interactive, or stdin is not a TTY) deploy fails with the full list of missing inputs instead of hanging on a prompt.Image build — with no
--image, deploy looks for a Dockerfile next to the graph:gpu.Dockerfilewhen the flow needs a GPU, elseDockerfile(falling back to whichever exists). Whether the flow needs a GPU is read from the config keys the template names inx-gpu(x-gpu: ['{device}']), else from the compiled graph’s device placement when the graph imports on this machine, else it is the CPU image with a note — never from whether this machine’s docker daemon has the NVIDIA runtime. The build context is the git root enclosing the graph (solution Dockerfiles COPY sibling packages from the repo root); override with--build-context. If the Dockerfile isFROMavideoflow-base:*image that is not built locally, deploy pullsghcr.io/videoflow/videoflow-base:<version>[-cuda]first and tags it under that name — or, on a source install, builds it from the checkout (a development version with no published image gets an error with the exact manual commands). The image is built asvideoflow-<solution-dir>:latestand deployed under a content-addressed tag (:<12 hex of its content digest>), so a changed image is always a new tag. Docker’s layer cache makes unchanged rebuilds take about a second. With no Dockerfile at all, the image is the base image itself — built from a source checkout (under a content-addressed tag, side-loaded or pushed like any built image), orghcr.io/videoflow/videoflow-base:<version>[-cuda]on a wheel install, which the pods pull — after a check that every Python node is one of videoflow’s built-ins, since the base image holds nothing else (a graph with its own node classes, or one that does not import on this machine, is refused with the fix: add a Dockerfile or pass--image).--no-builddisables all of this;VF_DOCKER_BUILD_ARGSadds arguments to everydocker build(a proxy). With--registry(usually from the cluster profile, below) a locally built image is then pushed and the pods pull the registry-qualified ref.Prepare hook — if the solution ships a
prepare.py, deploy runs it inside the built image (docker run, with--gpus allwhen available, plusVF_DOCKER_RUN_ARGS) before compiling, because its outputs (calibration files, model weights, …) get baked into the compiled node parameters. The solution directory and every resolved mount (see step 5) are volume-mounted into the container at their host paths, so all paths in the config resolve identically, and the resolved config path travels asVF_SOLUTION_CONFIG(abuild_flowthat reads it honours--configkept elsewhere). Skip with--no-prepare. Hooks are expected to be idempotent (skip finished steps), so re-running deploy is cheap.Compile — deploy calls your
build_flow()factory and compiles the graph to node specs. If the graph’s dependencies import on the operator machine this happens in-process; otherwise deploy runspython -m videoflow.compileinside the solution image and reads the specs back as JSON (the same serialization the provision Job uses). Either way the operator machine only needsvideoflow[deploy]— never the ML stack.Mounts — hostPath volumes from the repeatable
--mount /abs/path[:/container/path][:ro]flag plus the solution template’sx-mountsare added to every node workload (Jobs, Deployments, StatefulSets — not the provision Job). The single-path form mounts the same absolute path on both sides, which is what a flow compiled against local files needs: the paths baked into node params must resolve identically inside the pods. Data that lives in the cluster rather than on your machine — a shared model cache, an RWX work directory on a multi-node cluster where no node’s own filesystem holds it — is mounted from an existing PersistentVolumeClaim with--mount-pvc claim:/path[:ro](or anx-mountsentrypvc:claim:/path[:ro]). The two compose by one rule: a--mountorx-mountshost path at or under a claim’s mount path is served by the claim in the pods (a hostPath there would shadow it with an empty directory on every node but one) and still by the host in the prepare/compile containers — at the same path when the mount is a same-path one, or, for an entry that remaps a directory onto the container’s home (~/.videoflow:/root/.videoflow), as asubPathof the claim.--mount-home DIRis what makes those cache entries land inside the claim’s directory: it is what~resolves to on the host side. Host paths are resolved to their real location (symlinks followed) before any of this.Cluster mechanics — deploy classifies the cluster kubectl points at (
k3s/kind/minikube/docker-desktop/ generic remote) from the kubectl context and node labels, then:loads every locally-built image into the cluster with the right mechanism (
kind load docker-image/minikube image load/docker save | k3s ctr images import; docker-desktop needs nothing). A registry-qualified image (--registry, or an--imagenaming one) is never side-loaded — the nodes pull it. A remote cluster with a locally-built image and no--registryis a hard error with push instructions — pods there can never see your local docker daemon.warns when hostPath mounts will not see your local filesystem (kind and minikube nodes are VMs/containers with their own filesystem) and what to do about it.
for flows with GPU nodes, preflights what the generated GPU manifests need — a node labeled
videoflow.io/gpu-pool=true, enough free units of each requested GPU resource to cover the whole flow’s demand (every replica claims its own devices exclusively; a partially-schedulable flow stalls), a placement for every pod on the per-node free counts (the total and the largest node are necessary, not sufficient: two nodes with 3 free GPUs each hold only two of threegpu_count = 2replicas), and a RuntimeClass where the NVIDIA runtime is an opt-in one (deploy puts thenvidiaclass the cluster registers on the GPU pods by itself, and announces it;--gpu-runtime-class NAMEchooses,noneopts out) — and prints copy-pasteable fix commands. These are warnings by default;--strict-preflightturns them into a non-zero exit before anything is applied. A pod listing the API refused is reported asunobservable GPU staterather than read as an idle pool — a warning for exclusive claims, fatal under--gpu-mode mix. See GPU allocation: the modes, sharing, and multi-GPU models for running more GPU nodes than you have GPUs.checks that the broker and payload store it is about to use can provide what every channel asks for —
reliable_workfor a BATCH flow,live_latestfor REALTIME, or whatever--require-profile CHANNEL=PROFILEnames. A broker or store this deploy provisions is judged by the profile it renders; one the namespace already runs (an earlier--keep-infra, a shared dev cluster) by the profile recorded on its Service (videoflow.io/profile), and the provision Job reads it back in-cluster before creating a stream; a bring-your-own--nats/--blob-redis-urlis read back live here (a short probe, before any infrastructure exists), and what the probe cannot read is reported as unknown, never assumed. A composition that definitely cannot provide a guarantee — an evictable cache brought as the store of a BATCH flow, a server without JetStream — stops the deploy before anything is applied (exit 2); an unobserved guarantee is a warning unless the operator named the profile with--require-profile, when it is refused too (exit 3). Nothing is quietly downgraded. Both shipped profiles admit BATCH and REALTIME flows: the dev Redis persists and never evicts (see step 7).
Broker infra — with no
--nats, deploy creates the namespace if needed and applies a dev NATS JetStream (and, when--blob-redis-urlis also omitted, a dev Redis for the large-payload blob store) into it, waits for the rollout, and derives the in-cluster URLs (nats://nats.<ns>.svc:4222,redis://redis.<ns>.svc:6379/0). A pre-existingnats/redisService in the namespace is reused and never owned; only components deploy itself created are labeledvideoflow.io/infraand torn down later. Each Service records the profile that rendered it (videoflow.io/profile); a deploy that reuses it adopts that profile — its stream copies follow the real broker — and a--broker-profilethat contradicts the record is refused rather than silently served the other shape. The dev profile is one emptyDir server each: the NATS file store and the Redis append-only file both live for the pod (a container restart replays them, a pod loss does not), and the Redis runsnoeviction— a blob is never dropped while a reader still holds it, which is what a BATCH flow’sreliable_workchannels require; a full store refuses a write instead (every key still carries a TTL, and the reconciler reclaims orphans, so that is what bounds memory).--broker-profile durablerenders a NATS StatefulSet with cluster routes and a PersistentVolumeClaim per pod plus the same Redis on a claim, sized with--broker-replicas N(odd, default 3) and--broker-storage-class NAME(defaultlocal-path); its claims are kept at teardown.--priority-class NAMEputs every pod the deploy creates — workers, provision Job and this broker — in that PriorityClass. For production, bring your own broker (the official NATS Helm chart) and pass--nats.Apply & run — the manifests are applied in two phases (broker provisioning Job first, then workers). A BATCH flow then runs to completion: deploy waits, dumps the logs of any failed node, and tears down the run’s workloads, broker streams, and the infra it created in step 7 (
--keepkeeps everything for debugging;--keep-infrakeeps just NATS/Redis so the next deploy reuses them). A REALTIME flow is left running and deploy prints the matchingvideoflow teardowncommand — but only after a bounded rollout check: deploy waits for every pod to become Ready (i.e.open()completed), and if a pod crash-loops, is OOM-killed, cannot pull its image, or sits unschedulable past a grace period, it dumps the pod logs and exits non-zero, leaving the flow running for inspection. A pod that is merely still loading when the check’s deadline (~150 s, sized to the startup-probe window) expires is reported as a warning, not a failure.
--dry-run prints all manifests to stdout — including the dev-infra
manifests whenever the broker would have been auto-provisioned — and
--render-only writes them plus a kustomization.yaml to --output
for a later kubectl apply -k. Neither touches the cluster.
Prerequisites
dockerandkubectlon the operator machine, kubectl configured against the target cluster (deploy never switches contexts).videoflow installed (
pip install 'videoflow[all]', see Installing Videoflow). The graph’s own dependencies are not required on the operator machine (see step 4).The graph: the
build_flow()module of a solution directory (the module plus whatever the solution ships next to it —config.template.yaml,prepare.py,[gpu.]Dockerfile,requirements.txt), named in one of three ways that differ only in where the directory comes from:A solution shipped with videoflow
A solution in another git repository
A solution on your disk
Command
videoflow deploy videoflow://toy_calculator,videoflow deploy videoflow-contrib://human_trackinggit clone <url>, then the local formvideoflow deploy path/to/my_solution/my_solution.py[:factory], or the directory itself:videoflow deploy path/to/my_solutionThe directory
solutions/<name>/ofgithub.com/videoflow/<repo>, fetched at the tag of your installed version into~/.videoflow/solutions/<repo>@v<version>/($VF_SOLUTION_REFpicks another ref);<repo>://reaches the videoflow repositories onlythe clone
the one you named; the directory form expects
<name>/<name>.py, the convention the shipped solutions followThe image
built from the solution’s
[gpu.]Dockerfilewith the clone root as build contextas local
built from the
[gpu.]Dockerfilenext to the graph, with the enclosing git root (else the directory, or--build-context) as context — yourCOPYpaths are relative to it. No Dockerfile: the base image for your version, for a flow of built-in nodes.--imageor a node’s ownimage=wins over bothconfig.yaml, outputsnext to the graph, in the clone (
--configkeeps them elsewhere)next to the graph
next to the graph
Where the deploy goes is never part of the argument: the current kubectl context, plus the cluster profile that names it (next section).
For GPU flows: cluster nodes with the NVIDIA device plugin and the
videoflow.io/gpu-pool=truelabel (deploy tells you the exact commands if they are missing).For a multi-node or shared cluster: a cluster profile (next section).
A disposable cluster
./scripts/kind-up.sh builds a local kind cluster set up exactly the way this
page describes — images side-loaded, NATS and Redis installed in a namespace, the
broker also published on the host — and ./scripts/kind-down.sh deletes it. It
is what the tests/integration/k8s suite deploys against on every CI build, so
it is also the shortest way to try a deploy without a real cluster. See
tests/integration/README.md.
The same suite runs against a shared, multi-node k3s cluster through
./scripts/k3s-test-up.sh, which verifies rather than creates: it checks the
kubeconfig and that the current context is the expected one (it never switches
it), then prepares only namespaced objects — the test namespace, an RWX claim the
pods and the host share (k8s/test-pvc.yaml), the dev broker, a NodePort — and
pushes the images to the cluster’s registry with scripts/push-images.sh
(crane, from user space, no docker restart). Every pod it creates carries
priorityClassName: cluster-batch so it yields to other tenants’ work.
One thing it has to arrange is worth knowing before you point a solution at any
kind cluster: a solution’s work_dir is hostPath-mounted into the worker pods at
the absolute path baked in at compile time, and a kind node has its own filesystem.
The cluster config bind-mounts the work root into the node at the same path, so
host, node and pod agree. Without that the flow runs, every pod exits zero, and the
artifacts are nowhere to be found.
Building the image manually
Videoflow publishes one base image per release (framework + broker client +
the built-in nodes’ dependencies: OpenCV, ffmpeg, Redis):
ghcr.io/videoflow/videoflow-base:<version> and :<version>-cuda.
Solution images build on top of it, adding your dependencies and your node
package so the worker can import your node classes by their module path:
# Dockerfile (see docker/user-image.example.Dockerfile)
FROM ghcr.io/videoflow/videoflow-base:1.0.2 # pin the version you installed
RUN pip install torch my-libs # your dependencies
COPY . .
RUN pip install . # your package
docker build -t ghcr.io/acme/app:v1 . # your image, FROM videoflow-base
docker push ghcr.io/acme/app:v1
A pure built-in flow needs none of this: with no Dockerfile and no --image
it deploys in ghcr.io/videoflow/videoflow-base:<version>. From a source checkout,
./docker/build-images.sh builds both bases locally (as
videoflow-base:py3.12 and :py3.12-cuda) from the code you are editing.
Option reference
--config PATH/--non-interactiveExplicit solution config; never prompt (fail listing missing inputs).
--image/--image-override NAME=REF/--no-build/--build-context PATH--imageis the default image for every node that didn’t declare its ownimage=and disables auto-build.--image-overridesets the image for one node and wins over both (repeatable).--build-contextoverrides the git-root build context.--registry HOST[:PORT][/PREFIX]/--push-tool {docker,crane}Push the built image (or a local
--image) to this registry and have the pods pull the registry-qualified ref — the way onto a multi-node cluster, where side-loading reaches one node only.dockerpushes through the daemon (which must trust the registry);cranepushes from user space with--insecure, for a plain-HTTP registry the daemon does not trust, and needscraneon PATH (the error tells you how to install it). Both usually come from the cluster profile.--image-pull-policy {Always,IfNotPresent,Never}imagePullPolicyfor every container, workers and the provision Job alike. Defaults toIfNotPresent, which is what lets a locally built image run: deploy loads it into the cluster itself, so there is nothing to pull — and because an auto-built image is deployed under a content-addressed tag, it stays right on a registry too: a changed image is a new tag. UseAlwaysonly for a registry image under a mutable tag you re-push yourself.--cluster NAME/--clusters-file PATHThe cluster profile to take defaults from (see Multi-node and shared clusters), and where the profiles file is (default
$VF_CLUSTERS_FILE, else~/.config/videoflow/clusters.yaml). Without--clusterthe profile whosecontextis the current kubectl context applies.--no-prepareSkip the solution’s
prepare.pyhook.--mount HOST[:CONTAINER][:ro]hostPath volume added to every node workload and to the prep/compile containers. Absolute paths; single-path form mounts the same path on both sides. Repeatable; solution
x-mountsare added automatically.--mount-pvc CLAIM:PATH[:ro]An existing PersistentVolumeClaim (in
--namespace) mounted atPATHin every node workload. A--mountorx-mountshost path at or underPATHis served by the claim in the pods (as asubPathwhen the entry remaps it) and by the host in the prep/compile containers. Repeatable; solutionx-mountsof the formpvc:CLAIM:PATHare added automatically.--mount-home DIRWhat
~in the solution’sx-mountsresolves to on the host side (default: your home directory). On a multi-node cluster point it inside the directory passed to--mount-pvc, so the caches the pods mount are the ones the prepare hook filled.--gpu-runtime-class NAMEruntimeClassNamefor the GPU pods. Default: the NVIDIA RuntimeClass the cluster registers (nvidiaon k3s, where the NVIDIA container runtime is opt-in and a GPU pod without it starts device-less), detected at deploy time and announced; a name chooses one,nonesets no class.--priority-class NAMEpriorityClassNamefor every pod this deploy creates — workers, the provision Job and any broker it provisions. The PriorityClass must exist.--broker-profile {dev,durable}/--broker-replicas N/--broker-storage-class NAMEShape of the auto-provisioned NATS/Redis when
--natsis omitted (step 7). Omitted, the deploy rendersdevfor what is missing and adopts whatever the namespace already runs.teardown --infrareads the profile from the record on thenatsService, or takes the same--broker-profile, so it deletes the right workload kinds.--require-profile CHANNEL=PROFILERequire a messaging profile (
live_latest,reliable_work,durable_control,replay_archive) on the named channel — the output of that node. The composition check is always binding for a definite incompatibility; naming a profile additionally refuses an unobserved guarantee (a bring-your-own store whose configuration could not be read back), and refuses a profile the flow type’s own streams cannot carry (reliable_workon a REALTIME channel) before anything is applied. Repeatable; also onrun-local, against the dev containers. The requests reach the provision Job and the workers asVF_PROFILE_REQUESTS_JSON: the Job admits the composition against the live broker before creating any stream and verifies the streams it created carry the requested profiles, and each worker verifies its own channel and its parents’ before it opens — a contradiction ends the worker with exit 2, an unreadable stream with exit 3.VF_ADMISSION_TIMEOUT_SECONDS(default 60) bounds those read-backs.The render also carries the run ledger: the
VF_NATS_URLConfigMap carriesVF_RUNTIME_STORE_URL(the blob Redis) and every node’s ConfigMapVF_PARENT_REPLICAS. The provision Job reads the ledger’s persistence back like the store’s: only a Redis withappendonly yesandnoeviction(both shipped profiles; not an evictable cache brought as--blob-redis-url) makes the ledger durable, and only then are at-least-once durables provisioned with an unbounded broker cap and their retry budget kept in the ledger, a singleton node’s partition leased to the one pod that holds it (a second pod started by hand is refused at bind time instead of splitting the work), and payload obligations reconciled from the ledger at start and periodically; against a cache the broker cap stays and the ledger is process-local.Every object of a run is named for it —
vf-<flow>-<run>-<node>and the run-wide-broker/-specs/-provisionConfigMaps and Job, with selectors carrying thevideoflow.io/run-idlabel — so two runs of one flow coexist in a namespace without applying over each other; only the NetworkPolicy is shared by the flow’s runs.--nats/--blob-redis-urlBring-your-own broker / blob store; omitting them auto-provisions dev equivalents in
--namespace(see step 7).--keep/--keep-infraAfter a BATCH run, keep everything / keep just the auto-provisioned NATS+Redis.
--flow-idA stable identifier used to name all resources. Reuse the same value to redeploy/update the same logical flow.
--run-idPer-run id that scopes this run’s broker streams (auto-generated otherwise). A new run id gives fresh streams; reuse it to target the same run.
--autoscaling/--max-replicasEmit a KEDA
ScaledObjectper processor that scales on broker backlog, usingnb_tasksas the minimum replica count. Only a processor that renders as a Deployment can be scaled: a BATCH flow’s nodes are Jobs, whose parallelism is fixed at creation, so--autoscalingon a BATCH flow is refused at render time (aCapabilityError) instead of emitting a scaler that would dangle on a Deployment that never exists. Partitioned and, without--gpu-autoscaling, GPU nodes keep their fixed scale. A scaler carries one trigger per parent and KEDA scales on the highest, so a join whose second input backs up is scaled too. A multi-parent join at one replica and a node that declarespartition_byatnb_tasks = 1also keep their declared scale: scaled by KEDA, the first would split every group’s halves across competing replicas and the second would split one key’s history across replicas bound to the same competing durable. Redeploy such a node at the replica count it should own its keys at instead.--single-runRefuse to start this run while another run of the same flow holds workloads in the namespace — decided before anything of the new run is created, so the active run is never reconfigured (exit 3,
VF_ACTIVE_RUN; a namespace that cannot be listed is not a free one). Without it runs of one flow coexist under their run-scoped names.--rollout-policy {drain,surge}How a node’s Deployment replaces its pods on an update.
drainrendersstrategy: Recreate— every old replica stops before a new one starts, which is what a GPU node needs when its devices cannot be held by two generations at once.surgerenders a rolling update with one extra replica and none unavailable, and is admitted against the GPU pool’s free devices: with nothing spare it is refused before anything is applied, because the replacement would wait forever behind the old pod. Omitted, the Kubernetes default rolling update stays — deploy warns when the pool is full, since that default stalls the same way.--gpu-nodes HOST[,HOST...]Pin every GPU pod to these hosts: a required
kubernetes.io/hostnamenode-affinity term on top of the pool label, for a shared cluster where only some GPU nodes are yours to use.--resources NODE=key:quantity[,key:quantity...]Host requests and limits for a node’s worker container —
cpuandmemoryare requests,cpu_limitandmemory_limitlimits;NODE=*applies to every node, a node entry overrides it, and both override a component descriptor’sspec.resources.cpu/memory. Repeatable. Host memory is a scheduler request, never a GPU memory declaration: a node whose replicas fit the GPUs but not a node’s RAM stays Pending with the scheduler’s reason instead of being admitted on GPU capacity alone.--gpu-mode draRender Dynamic Resource Allocation claims instead of an extended-resource limit (see GPU allocation: the modes, sharing, and multi-GPU models); needs a GPU DRA driver in the cluster.
--dry-run/--render-only/--outputManifest generation without touching the cluster (see above). With a
--registry,--render-onlypushes the image (its output is meant to be applied) while--dry-runonly names the registry ref it would push.
Other CLI commands
videoflow explain my_flow.pyPrint a human-readable summary of the compiled graph — nodes, replicas, image families, partitioning, subjects, and the DLQ stream — without touching a cluster. A solution’s config is resolved exactly as
deploydoes it (--config, elseconfig.yamlbeside the graph, else the template’s questions —--non-interactivelists them instead of asking), soexplainworks before the first deploy has written one.videoflow --versionThe installed version — also the tag
<repo>://<name>references are fetched at, and theghcr.io/videoflow/videoflow-basetag a wheel install pulls.videoflow provision my_flow.py --nats ...Create the flow’s broker streams and durable consumers up front. This normally happens automatically (a generated init Job on Kubernetes, or the local engine before it spawns workers), but is exposed for manual/debug use.
videoflow teardown --flow-id ... --run-id ... --nats ... [--namespace ...] [--infra]Stop a run (control-channel signal) and delete its broker streams; with
--namespaceit alsokubectl deletes the flow’s workloads, and with--infrait deletes auto-provisioned NATS/Redis (only resources labeledvideoflow.io/infra— a bring-your-own broker is never touched). This is the escape hatch for REALTIME flows deployed with auto-infra. Streams are matched by exact ownership, never by name prefix; if the stream listing failed or a delete did not land, teardown printsWARNING: broker cleanup incomplete ...naming what remains and carries on — re-run it once the broker answers.python -m videoflow.compile graph.py[:factory]Compile a graph to a JSON specs document on stdout — what deploy runs inside the solution image when the graph can’t be imported on the operator machine.
videoflow run-local graph.py [--in-image] [--mount ...] [--mount-home DIR]The local twin of
deploy: the same config Q&A and prepare hook, a dev NATS/Redis started in docker when nothing is listening, one worker subprocess per node replica. When the graph’s dependencies are not installed on this machine — the ML solutions of videoflow-contrib — the prepare hook and every worker run inside the solution image instead (built exactly as deploy would, and reused by it), with the solution’sx-mountsand any--mountas bind mounts and, when the docker daemon has the NVIDIA runtime, each worker’s granted devices passed with--gpus.--in-imageforces that even for a graph that imports here.
How graph concepts map onto Kubernetes
Concept |
Behavior |
|---|---|
|
broker keeps only the freshest message per edge |
|
at-least-once, loss-free delivery (interest retention + backpressure); failures retry then dead-letter to a DLQ |
|
N Deployment replicas (competing consumers), each claiming a replica slot through the run ledger at start; in a BATCH flow an Indexed Job of N completions (index = replica id) |
|
N StatefulSet replicas, partitioned by key (scales joins); not autoscaled |
|
pod requests |
finite producer ( |
a Kubernetes Job |
infinite producer / processor / consumer |
a Kubernetes Deployment |
|
control-channel signal, then the workloads are torn down |
|
hostPath volume + volumeMount on every node workload |
|
|
Observability
Every worker pod exposes an HTTP endpoint (port 8080) with:
/readyz— readiness: turns healthy only after the node’sopen()completes, so a pod whose model is still loading is not sent traffic./healthz— liveness: a heartbeat updated on every loop iteration; a stalled worker is restarted./metrics— Prometheus metrics: per-node processing-time histograms (_bucket{le=...}plus_count/_sum), throughput and drop counters, and errors by code and disposition.
The generated Deployments/Jobs reference the readiness and liveness probes automatically. See Debugging flow applications.